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  • Percentage of Methanol

    Hello,
    I had a query about the percentage of methanol to use that I included in a post in a different thread, but didn't get much response from it (there were also a million other questions posed in the thread), so I thought I would open a new thread to discuss it.
    I know that there are some schools of though that think only 15% is required, while others think 25%. As methanol is the most expensive ingredient for the process, I think it's important to know the minimial amount required to create an acceptable batch of bio.
    I previously used 20% for my batch, but mistakenly overdosed one batch and used almost 30%. At the end, I found this overdosed batch significantly clearer in comparison to the 20% batch. Does this suggest that 25% is required for conversion?
    I've also read that it is a good idea to increase the percentage of methanol in the winter, but it said to increase from 15 to 20%, so 25% still seems high to me.
    What do you guys think or what are you using?

    Dave

  • #2
    Re: Percentage of Methanol

    Hello Dave,
    The chemist Neutral did some GC testing that showed that it required about 7g KOH mixed into 200ml per litre new oil to barely achieve ASTM conversion (98+%)
    This converts to 5g NaOH.
    The vast majority of diesel engines do not seem to require ASTM conversion biodiesel.
    My thoughts are that 15- 18% methanol is plenty for winter Biodiesel in sunny ลึก ประเทศอินเด&
    The higher the conversion the lower the viscosity so the easier it is to inject when it is cold.

    Tilly

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    • #3
      Re: Percentage of Methanol

      Dave,
      If you plan to build a methanol recovery facility, you can use 25% methanol and recover the unused methanol from the biodiesel and byproduct after separation. In this way, you will be profucing high quality biodiesel without any additional cost.
      Tony
      Life is a journey, with problems to solve, lessons to learn, but most of all, experiences to enjoy.

      Current Vehicles in stable:
      '06 Musso Sports 4X4 Manual Crew Cab tray back.
      '04 Rexton 4X4 Automatic SUV
      '2014 Toyota Prius (on ULP) - Wife's car

      Previous Vehicles:
      '90 Mazda Capella. (2000 - 2003) My first Fatmobile. Converted to fun on veggie oil with a 2 tank setup.
      '80 Mercedes 300D. 2 tank conversion [Sold]
      '84 Mercedes 300D. 1 tank, no conversion. Replaced engine with rebuilt OM617A turbodiesel engine. Finally had good power. Engine donor for W123 coupe. (body parted out and carcass sold for scrap.)
      '85 Mercedes Benz W123 300CD Turbodiesel
      '99 Mercedes W202 C250 Turbodiesel (my darling Wife's car)[sold]
      '98 Mercedes W202 C250 Turbodiesel (my car)[sold]
      '06 Musso Sports Crew Cab well body. [Head gasket blew!]
      '04 Rexton SUV 2.9L Turbodiesel same as Musso - Our Family car.
      '06 Musso sports Crew Cab Trayback - My hack (no air cond, no heater).

      Searching the Biofuels Forum using Google
      Adding images and/or documents to your posts

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      • #4
        Re: Percentage of Methanol

        Another point to consider is whether you are going to wash the biodiesel. If you are going to wash, then go for the higher percentages of methanol. The lower conversion biodiesel will have a lot of mono-glyerides in it that will bind with the water and create a white cream like substance - commonly referred to as the dreaded white stuff.

        You can use a pre-wash on low conversion biodiesel without getting the dreaded white stuff. It is the subsequent water washes that create the muck.
        Terry Syd
        Senior Member
        Last edited by Terry Syd; 1 May 2006, 06:41 AM.

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        • #5
          Re: Percentage of Methanol

          hmmmm only 7g KOH eh? I've been using 7.7 as my base amount......that too much then?
          Tony - no I won't have the capacity to build a methanol recovery unit on the road, so I won't be able to recover the methanol, even though I would love to be able to do that
          Terry - right now I'm thinking that I will just do a pre-wash, perhaps 10-15%. So therefore I could stick with my 20% methanol?

          I am going to go and make a couple batches right now, so I think I will stick with my 20%. Although I've already made a batch with 25%, so I can see how that compares and let everyone know.

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          • #6
            Re: Percentage of Methanol

            hello Dave,
            7g KOH if it is 100% pure.
            7.8g KOH if it is 90% pure.

            Tilly

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            • #7
              Re: Percentage of Methanol

              I am using 100% fresh canola oil from supermarket shelf to understand the how increasing KOH (85%) will affect the ester content...

              Can somebody please post:

              1. What should be the KOH content for 1ltr of oil. I am using 220ml of methanol for 1lit of oil. I want to get close to 98% conversion.

              2. Any trends and data you have on increase in ester content with increase in KOH?

              Any suggestions are welcome.

              TassieDevil

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              • #8
                Re: Percentage of Methanol

                I would be very interested in your conclusions. I have heard anywhere from 4.5g of KOH/L as a base to 7.8g of KOH/L.....so there is a big range out there.

                Dave

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                • #9
                  Re: Percentage of Methanol

                  Hello TassieDievel and Dave

                  Unlike NaOH which normally comes in the 100% flavour, KOH comes in many flavours.
                  If you can get the KOH flavour that is 100% (Not too common) then you can just go along with Neutral's test results which showed that to just scrape into ASTM conversion when reacting a lire of new oil requires 7g KOH mixed into 205ml methanol. We usually just round that down to 200ml for good luck.

                  If your KOH is only 90% then you need to make an adjustment to the amount of KOH to use.
                  The maths I use to figure this out (Which may be incorrect)
                  100/90= 1.11x7= 7.77 = 7.8g KOH

                  If your KOH is 85% then it looks like:
                  100/85= 1.18x7= 8.26= 8.3g KOH

                  Tests have shown that if you increase the quantity of reactants the conversion increases.
                  Tests show that KOH is unlikely to cause a gel.
                  Tests show that Methanol is more expensive than KOH.
                  Tests show it is more cost effective to increase the amount of caustic rather than the amount of methanol if you wish to achieve a conversion more than 98% (to a point)

                  I recommend that if you choose to use 220ml methanol in the reaction then to obtain maximum "Bangfor your Buck" you should increase the KOH too. Otherwise you are wasting methanol by not obtaining the highest conversion possible considering the amount of methanol in the reaction.
                  In this case I would UP the KOH by at least 2 points on the 100% KOH scale.

                  Do be aware that there are very few diesel engines that require ASTM conversion biodiesel.
                  Also be aware that the European standard only requires 96.5% conversion.
                  I haven't a clue what the Australian standard is.

                  Tilly
                  tillyfromparadise
                  Senior Member
                  Last edited by tillyfromparadise; 1 May 2006, 10:32 PM.

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                  • #10
                    Re: Percentage of Methanol

                    Last time I looked it was 96%.

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                    • #11
                      Re: Percentage of Methanol

                      Thanks Tilly :

                      Has there been any posts that highlight conversion rates based on the amount of KOH used in these threads..

                      Has anybody used 7.8gms of KOH for FVO with 200ml methanol to see the ester conversion as a percentage? say >96.5%

                      please post any results or experience..

                      Tassie

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                      • #12
                        Re: Percentage of Methanol

                        Hello Tassie

                        FVO?

                        Tilly

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                        • #13
                          Re: Percentage of Methanol

                          My apologies...Fresh Vegetable Oil (FVO)..Tassie

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                          • #14
                            Re: Percentage of Methanol

                            Hello TassieDievel
                            FVO?

                            There is no TLA for new veggie oil.
                            Some people think SVO, Straight Vegetable Oil means new as "Straight out of the bottle", but alas it really means straight as in not transesterfied.
                            SVO is more often used oil except in the UK where a lot of fellows use new oil.

                            I personally like NVO.

                            Tilly
                            tillyfromparadise
                            Senior Member
                            Last edited by tillyfromparadise; 10 May 2006, 06:41 PM.

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                            • #15
                              Re: Percentage of Methanol

                              Hi everyone! i just want to ask if there is a certain way to test the % purity of methanol recoverred from distillation; we are using the specific gravity of the methanol to know its purity but i think this will have error, how can i be sure that we are producing high purity of methanol? (i'm working on a coco bio diesel company). please help

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